The world owes a debt to the United States for its leadership in the fight against international terrorism, Prime Minister Gordon Brown has said.

Arriving for his first formal talks as PM with President Bush, he said the UK's "most important bilateral relationship", was that with the US.

A foreign office minister had suggested the two countries would no longer be "joined at the hip" on foreign policy.

Talks at Camp David later are expected to include Iraq, Darfur and Kosovo.

International issues

UK Foreign Secretary David Milliband and US Secretary of State Condoleezza Rice are expected to be at the talks, which are also likely to include world trade, climate change, the Middle East and Afghanistan.

Analysts will be looking for signs of the Brown regime distancing itself from the US during the trip.

BBC political editor Nick Robinson said Mr Brown was "walking a tightrope" in his dealings with America.

Private dinner

He needed to reassure Mr Bush of his commitment to the Atlantic relationship as well as convince British voters that links between the US and the UK would be different to those maintained by former prime minister Tony Blair, our correspondent said.

The prime minister flew to Camp David for a private dinner with the president on Sunday night at his Maryland retreat.

He heads to Washington on Monday for cross-party talks with senate leaders and members of congress.

Earlier this month, Foreign Office Minister Lord Malloch Brown said it was time for a more "impartial" foreign policy and for Britain to build relationships with European leaders.

We should acknowledge the debt the world owes to the United States for its leadership in this fight against international terrorism

But en route to the US, Mr Brown described himself as an "Atlanticist and a great admirer of the American sprit".

"As prime minister I want to do more to strengthen even further our relationship with the US," he said.

"It is firmly in the British national interest that we have a strong relationship with the US, our single most important bilateral relationship."

Close relationship

Mr Brown said the shared ideals of two centuries of history "have linked the destinies" of the two countries.

He also quoted Winston Churchill - the first British prime minister to visit Camp David - who also spoke of a "joint inheritance".

This close relationship would help in the fight against nuclear proliferation, global poverty, climate change and global terrorism, Mr Brown said.

Our relationship with America should be what we call solid but not slavish

William HagueShadow foreign secretary

"And we should acknowledge the debt the world owes to the United States for its leadership in this fight against international terrorism," he added.

Tony Blair enjoyed a close relationship with Mr Bush but there has been speculation that Mr Brown wants to keep his distance from the president.

The shadow foreign secretary, William Hague, told the BBC the prime minister and foreign secretary needed to set a clear stance.

'Candid friend'

He said: "They should not be leaving it to more junior ministers to create misunderstandings about the relationship with America, which is what has happened over the last few weeks.

"Our approach, the approach David Cameron and I take, is that our relationship with America should be what we call solid but not slavish and it should gain frankness without losing its closeness."

Liberal Democrat leader Menzies Campbell said three main issues should be discussed at the meeting.

It's clear to us that he wants a strong relationship with the United States

David JohnsonUS Embassy

"Renegotiation of the one-sided extradition treaty, the closure of the Guantanamo Bay detention centre and a negotiated withdrawal of British forces from Iraq," he said.

"These should be the objectives of a candid friend. The excessively subordinated relationship between the president and Mr Blair should be put to bed."

But David Johnson, the deputy chief of mission at the US embassy in London, told BBC Radio 4's Today programme people were getting "a little obsessive...about the parlour game of how close people might be sitting to one another on the couch".

"It's clear to us that he [Gordon Brown] wants a strong relationship with the United States, that he is in pursuit of one," he said.